Copper recovery from small devices populated on waste printed circuit boards

Present study discusses the recovery of copper (Cu) from discarded small devices depopulated from waste printed circuit boards (WPCBs) and the same get discarded during its manufacturing. Among all small components, semiconductor devices, especially, metal oxide semiconductor field effect transistors (MOSFETs) are in abundant and selected for Cu recovery. MOSFETs were crushed, leached in HNO₃ and the results were validated thermodynamically. Almost 99% Cu was recovered using 3M HNO₃ at 90°C for 30 min maintaining pulp density 10 g/L. Leach liquor generated was mixed with tri-butyl phosphate (TBP) to extract HNO₃ completely, which requires 3 stages at O/A ratio 3:1 and mixing time 15 min. Further, air sparging was carried out to remove the Fe content from the solution in order to intensify the efficiency of electrowinning later used to extract pure Cu metal sheet from the solution. The spent electrolyte containing other metals can be stored for further processing or sent to effluent treatment plant.